Die-operating means for duplex head nail machines



Sept- 4, 1956 c. E. CHISM 2,761,157

DIE-OPERATING MEANS FOR DUPLEX HEAD NAIL. MACHINES Filed June 23, 1.9532 Sheets-Sheet l (Mem/5ft.' (Af/5M Sept 4, 1956 c. E. cHlsM 2,761,157

DIE-OPERATING MEANS FOR DUPLEX HEAD NAIL. MACHINES Filed June 23, 1953 2Sheets-Sheet 2 Fnsi- A u OMM/@ @degli United States Patent ODIE-OPERATING MEANS F R DUPLEX HEAD NAIL MACHINES Clarence E. Chism,Pittsburg, Calif.

Application June 23, 1953, Serial No. 363,531

3 Claims. (Cl. 10-53) This invention relates to improved die-operatingmeans for duplex head nail machines.

2,761,157 lPatented Sept. 4, 1956 ICC v respect to the wire stock andare shown only diagram- A duplex head nail has a second head spacedaxially 'i' from the usual head at the nail end. Such nails commonly aremanufactured from wire stock in a machine which includes the usual feedmechanism, wire gripping dies, reciprocable hammer, and cut-offmechanism, and in addition a second set of longitudinally movablegripping dies situated between the first dies and the hammer. The firstdies occupy a fixed position longitudinally of the wire, although ofcourse at least one of them moves radially of the wire for alternatelygripping and releasing the wire. When both sets of dies are gripping theWire, a single blow of the hammer simultaneously upsets both heads onone nail. The head at the nail end is upset between the hammer and thelongitudinally movable dies. The head which is spaced from the end isupset between the two sets of dies. An exemplary machine of this kind isshown in Little et al. Patent No. 2,381,171, dated August 7, 1945, andreference can be made thereto for a more detailed understanding.

These machines include a mechanism which continuously urges thelongitudinally movable dies in the exit direction away from thelongitudinally fixed dies. An object of the present invention is toprovide an improved mechanism for this purpose, that is, a mechanismwhich has a long life, which is not subject to clogging from nailwhiskers produced during cutting, and which is easily accessible.

A more specific object is to provide an improved dieoperating mechanismwhich includes .depending spring pressed rods that urge thelongitudinally movable dies forward against their holders, the mountingbeing clear of any nail whiskers and readily accessible.

In accomplishing these and other objects of the invention, I haveprovided improved details of structure, a preferred form of which isshown in the accompanying drawings, in which:

Figure l is a top plan View of a portion of a duplex head nail machinewhich has a die-operating mechanism constructed in accordance with myinvention;

Figure 2 is a vertical section on line II--II of Figure 1;

Figure 3 is a perspective view of the dies and die holders;

Figure 4 is a horizontal sectional view showing the relation of the diesas they grip the wire stock before the hammer strikes the latter;

Figure 5 is a view similar to Figure 4, but showing the position as thehammer strikes a blow; and

Figure 6 is another view similar to Figure 4, but showing the positionafter the dies have retracted, the stock has been fed another increment,and the blades have severed a finished nail therefrom.

Figures l and 2 show a die block 10 which is adapted to be fixed to thebedplate of a -duplex head nail machine. The die block carries a pair ofdie holders and dies 12 and 12a which occupy a xed longitudinal positionwith matically, and a second pair of die holders 13 and 13a situated atthe exit side of the first pair. As best shown in Figure 3, the faces ofthe die hol-ders 13 and 13a at their entry side (i. e., the facesdirected toward the die holders 12 and 12a) contain grooves 14 and 14a.Dies 15 and 15a are mounted in said grooves and are pivoted to theirrespective die holders` on vertical pins 16 and 16a situatedadjacent theouter ends of the dies. Thus the inner ends of the dies 15 and 15a canmove longitudinally of the wire. The inner ends of the four dies arenotched to grip a wire W from which duplex head nails N are formed, InFigures 4, 5 and 6 the hammer of the ma-4V chine is indicateddiagrammatically at 17 and the cutters' In accordance with the usualoperation of such ma?- c hines, both sets of dies simultaneously closeon the WireA W after it has been fed to the proper position (Figure 4).

The hammer 17 advances and with a single blow upsets` `a first head H1on the end portion of the wire which proytrudes beyond the dies 15 and15a and a second head H2 retracted position. The present inventionaffords a mechanism for retracting these dies, as hereinafter explained.Thereafter both sets of dies release the wire W, which feeds forward oneincrement (Figure 6). The cutters 18 then cut the finished nail N fromthe wire and form the point thereon. The sequence just described isrepeated for each nail. The feed mechanism and the operating means forthe Various mechanisms, other than the longitudinally movable dies, arenot involved in the present invention, and therefore no showing is made.Nevertheless reference can be made to the aforementioned Little et al.patent for a complete showing of typical mechanisms of this kind andtheir operating means.

In accordance with the present invention, the upper face of the dieblock 10 carries a U-shaped yoke 19 rigidly attached thereto (Figures land 2). A fixed horizontal shaft 20 extends between the upstanding armsof said yoke substantially the length of the die block. A pair ofapproximately horizontal arms 21 and 21a are pivotally mounted on saidshaft. A coil spring 22 surrounds the portion of the shaft above the die15 and has a loop 23 that bears downwardly against the back portion ofthe arm 21. The outer end of said spring is fixed to a bolt 24 carriedby the upstanding arm of the yoke 19. The inner end of said spring isfixed to a bolt 25 carried by the midportion of the shaft 20. A secondcoil spring 22a is similarly related to the portion of the shaft 20above the die 15a and the arm 21a.

The die block 10 contains a pair of vertical bores 26 and 26a. Theforward portions of the arms 21 and 21a carry depending rods 27 and 27arespectively that extend loosely through these bores and bear againstthe rearward faces of the dies 15 and 15a. The rearward faces of the dieholders 13 and 13a are recessed as indicated at 28 to accommodate saidrods. The springs 22 and 22a continuously bear downwardly against theback portions of the arms 21 and 21a and thus urge the rods 27 and 27aand the dies 15 and 15a forwardly toward the retracted position of thelatter. These springs are readily yieldable when the hammer 17 strikes`to enable the dies to pivot with the hammer blow, but they immediatelyreturn the dies to their retracted position when the hammer retracts.

It is seen that my invention places the operating means for thelongitudinally movable dies at a location which is easily accessible andalso well removed from the cutters Next the hammer retracts, and the4dies v15 and 15a also pivot `forwardly back to their tothe disclosureset forth but only by the scope of the appended claims.

I claim:

l. In a Iduplex head nail machine which includes a die block, a set oflongitudinally fixed dies mounted on said die block for alternatelygripping and releasing wire stock, an additional set of die holdersmounted in said die block on the exit side of said longitudinally fixeddies, and a set of longitudinally movable dies pivoted to saidadditional die holders on the side toward said longitudinally xed dies,the combination therewith of a mechanism urging said longitudinallymovable dies to a retracted position away from said longitudinally xeddies, said mechanism comprising upright support means carried by theupper face of said die block, a shaft mounted on said support means,arms pivoted on sai-d shaft to turn on a horizontal axis, rods dependingfrom each of said arms and bearing against said longitudinally movabledies, and spring means carried by said shaft above said die block andacting on said arms to urge said rods against said longitudinallymovable dies, said die block and said additional die holders havingvertical passages accommodating said rods.

2. A combination as defined in claim 1 in which the spring means includecoil springs surrounding said shaft and having loops in engagement withsaid arms.

3. In a duplex head nail machine which includes a die block, a set oflongitudinally xed dies mounted in said die block for alternatelygripping and releasing Wire stock, an additional set of die holdersmounted in said die block on the exit side of said longitudinally fixeddies, and a set of longitudinally movable dies pivoted to saidadditional die holders on the side toward said longitudinally xed dies,the combination therewith of a mechanism urging Said longitudinallymovable dies to a retracted position away from said longitudinally xeddies, said mechanism comprising support means carried on the upper faceof said die block and extending thereabove, pivotal mounting meanscarried by said support means, depending rods supported from saidmounting means and bearing against said longitudinally movable dies, andspring means carried by said mounting means above said die block andurging said rods against these dies, said die block an-dradditional dieholders having vertical passages accommodating said rods.

References Cited in the tile of this patent UNITED STATES PATENTS467,362 Blackburn Ian. 19, 1892 1,693,664 Petitjean Dec. 4, 19282,381,171 Little et al. Aug. 7, 1945 FOREIGN PATENTS 333,351 GermanyFeb. 22, 1921

